Activity of an atypical Arabidopsis thaliana pectin methylesterase.
An Arabidopsis thaliana pectin methylesterase that was not predicted to contain any signaling sequence was produced in E. coli and purified using a His tag added at its N-terminus. The enzyme demethylesterified Citrus pectin with a Km of 0.86 mg/ml. The enzyme did not require salt for activity and was found to be relatively temperature-sensitive. The precipitation of enzyme-treated pectin by CaCl2 suggested that the enzyme had a blockwise mode of pectin demethylesterification. A purified kiwi (Actinidia chinensis) pectin methylesterase inhibitor had no effect on the activity of the enzyme whereas it strongly inhibited a flax pectin methylesterase. A model of the protein structure revealed that an extra amino acid sequence in this particular Arabidopsis pectin methylesterase could form a ss-strand outside the core structure, which might be preventing the inhibitor from binding the protein.
Dedeurwaerder
Sarah
S
Université de Picardie Jules Verne, 33 rue St Leu, 80039, Amiens, France.
Menu-Bouaouiche
Laurence
L
Mareck
Alain
A
Lerouge
Patrice
P
Guerineau
François
F
D029042:Actinidia / Q000201:enzymology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D020134:Catalytic Domain; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein
D029681:Arabidopsis Proteins; D004791:Enzyme Inhibitors; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase